The Vigdis oil and gas field is situated in block 34/7 of the Tampen area in North Sea, Norway. Situated at a water depth of 280m, the field comprises two other discoveries including Vigdis East and Borg North-West.
First production from Vigdis was achieved in 1997. The field is expected to continue producing until 2020. Production from the Borg North-West (or Vigdis extension) and Vigdis East discoveries commenced in 2003 and 2004 respectively.
Vigdis was originally licensed to Saga Petroleum. Norsk Hydro became the operator following its acquisition of Saga in 1999. Statoil, which has 41.5% interest in the field, became the operator in January 2003.
Other partners include Petoro (30%), ExxonMobil E&P Norway (10.5%), Idemitsu Petroleum Norge (9.6%), Total E&P Norge (5.6%) and RWE Dea Norge (2.8%).
Vigdis was discovered in 1986 by discovery well 34/7-8. In March 2009, additional reserves were discovered north of the Vigdis East field by an exploration well 34/7-34. The well was drilled by the Borgland Dolphin drilling rig and sidetracked to confirm the presence of hydrocarbons in the Statfjord group formation of the lower Jurassic age.
Recoverable reserves at Vigdis are estimated at 390 million barrels of crude oil and 64bcf of gas. The drilling activities north of the Vigdis East field confirmed proven recoverable resources of 25 million barrels of oil. The discovery termed Vigdis North-East has been put on fast track development.
The Vigdis field reservoir consists of Brent group formations of the middle Jurassic age. The Vigdis East reservoir is made of the Statfjord formation of the lower Jurassic and upper Triassic age.
The Borg North-West reservoir consists of intra-Draupne sandstones of the upper Jurassic age. Depth of the reservoirs ranges from 2,200m to 2,600m.
Vigdis field development
The Vigdis field was developed using four subsea templates for the main Vigdis field structure, the Borg North-West field and the Vigdis East field. A total of 12 wells, including four injection wells, were drilled to develop the fields. The subsea equipment is tied back to the Snorre A tension leg platform at the Snorre oil field, which is located 7km away.
The Borg North-West and the Vigdis East fields were developed in two phases under the Vigdis extension project. The extension enabled recovery of an additional 50 million barrels of oil.
Phase I of the extension included installation of two seabed templates and two satellite structures on the Borg North-West field. Three production and three injection wells were drilled during this phase.
Phase II required an investment of $180m. A third template was installed and one production and one water injection well were drilled on the Vigdis East field during this phase. The template featuring four well slots commenced production in April 2008.
Snorre A tension leg platform
Snorre A has been operating at the Snorre field since 1992. It is installed at a depth of 305m and moored by a steel tethered system. It features a separate processing module to process the well stream produced at the Vigdis field.
Production and export
Oil is recovered by applying partial pressure on the reservoir through water injection. It is processed at the Snorre A platform and transported to the Gullfaks A platform for storage and export. Gas recovered at the main Vigdis field is injected into the Snorre field reservoir.
Gas recovered from the Borg North-West and Vigdis East fields is sent to Snorre A and Statfjord A platforms for processing.
The processed gas is transported by the Statpipe / Norpipe system to different markets.
Statoil has undertaken an upgrade programme called Tordis Vigdis controls modification (TVCM) project for the Tordis and Vigdis fields. In June 2009, GE Oil & Gas was awarded a $70m contract to supply its VetcoGray SemStar5 subsea control module for the fields. Offshore installation of the modules is expected to be carried out between 2010 and 2011.
ClampOn was contracted to supply funnels and sensors for the subsea modules of the TVCM project.
In December 2010, FMC Technologies won a $75m contract for supplying subsea equipment for the Vigdis North-East field. The contract includes supply of subsea trees, a manifold and umbilical and other equipment. Deliveries are expected to start in the third quarter of 2011.
FMC Technologies supplied subsea equipment for phase II of the Vigdis extension project under a $25m contract awarded in 2006. The equipment included four subsea trees, a manifold and control system, a subsea control cable and control system. The company also provided system integration, installation and maintenance services.
NKT Flexibles supplied two water injection replacement lines, jumpers and flowlines for the Vigdis field and the Vigdis extension project.
In 2002, Stolt Offshore was awarded a Nkr535m contract to supply 23km of 6in and 12in flowlines and umbilicals.
Theta Norge provided consultancy services for laying of the Vigdis subsea flow lines.